/* LibTomCrypt, modular cryptographic library -- Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. * * Tom St Denis, tomstdenis@gmail.com, http://libtom.org */#include "tomcrypt.h"/**   @file omac_done.c  LTC_OMAC1 support, terminate a stream, Tom St Denis*/#ifdef LTC_OMAC/**  Terminate an LTC_OMAC stream  @param omac   The LTC_OMAC state  @param out    [out] Destination for the authentication tag  @param outlen [in/out]  The max size and resulting size of the authentication tag  @return CRYPT_OK if successful*/int omac_done(omac_state *omac, unsigned char *out, unsigned long *outlen){   int       err, mode;   unsigned  x;   LTC_ARGCHK(omac   != NULL);   LTC_ARGCHK(out    != NULL);   LTC_ARGCHK(outlen != NULL);   if ((err = cipher_is_valid(omac->cipher_idx)) != CRYPT_OK) {      return err;   }   if ((omac->buflen > (int)sizeof(omac->block)) || (omac->buflen < 0) ||       (omac->blklen > (int)sizeof(omac->block)) || (omac->buflen > omac->blklen)) {      return CRYPT_INVALID_ARG;   }   /* figure out mode */   if (omac->buflen != omac->blklen) {      /* add the 0x80 byte */      omac->block[omac->buflen++] = 0x80;      /* pad with 0x00 */      while (omac->buflen < omac->blklen) {         omac->block[omac->buflen++] = 0x00;      }      mode = 1;   } else {      mode = 0;   }   /* now xor prev + Lu[mode] */   for (x = 0; x < (unsigned)omac->blklen; x++) {       omac->block[x] ^= omac->prev[x] ^ omac->Lu[mode][x];   }   /* encrypt it */   if ((err = cipher_descriptor[omac->cipher_idx].ecb_encrypt(omac->block, omac->block, &omac->key)) != CRYPT_OK) {      return err;   }   cipher_descriptor[omac->cipher_idx].done(&omac->key);    /* output it */   for (x = 0; x < (unsigned)omac->blklen && x < *outlen; x++) {       out[x] = omac->block[x];   }   *outlen = x;#ifdef LTC_CLEAN_STACK   zeromem(omac, sizeof(*omac));#endif   return CRYPT_OK;}#endif/* $Source: /cvs/libtom/libtomcrypt/src/mac/omac/omac_done.c,v $ *//* $Revision: 1.9 $ *//* $Date: 2007/05/12 14:37:41 $ */